yield* calls @@iterator on iterable

src/preparser.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_PREPARSER_H
 #define V8_PREPARSER_H
 
 #include "src/v8.h"
 
 #include "src/func-name-inferrer.h"
@@ skipping 1214 matching lines @@
   static PreParserExpression ExpressionFromIdentifier(
       PreParserIdentifier name, int pos, PreParserScope* scope,
       PreParserFactory* factory) {
     return PreParserExpression::FromIdentifier(name);
   }
 
   PreParserExpression ExpressionFromString(int pos,
                                            Scanner* scanner,
                                            PreParserFactory* factory = NULL);
 
+  PreParserExpression GetIterator(PreParserExpression iterable,
+                                  PreParserFactory* factory) {
+    return PreParserExpression::Default();
+  }
+
   static PreParserExpressionList NewExpressionList(int size, void* zone) {
     return PreParserExpressionList();
   }
 
   static PreParserStatementList NewStatementList(int size, void* zone) {
     return PreParserStatementList();
   }
 
   static PreParserExpressionList NewPropertyList(int size, void* zone) {
     return PreParserExpressionList();
@@ skipping 842 matching lines @@
         // a Yield::SUSPEND operation, given only one look-ahead token.
         if (kind == Yield::SUSPEND)
           break;
         DCHECK(kind == Yield::DELEGATING);
         // Delegating yields require an RHS; fall through.
       default:
         expression = ParseAssignmentExpression(false, CHECK_OK);
         break;
     }
   }
+  if (kind == Yield::DELEGATING) {
+    // var iterator = subject[Symbol.iterator]();
+    expression = this->GetIterator(expression, factory());
+  }
   typename Traits::Type::YieldExpression yield =
       factory()->NewYield(generator_object, expression, kind, pos);
   if (kind == Yield::DELEGATING) {
     yield->set_index(function_state_->NextHandlerIndex());
   }
   return yield;
 }
 
 
 // Precedence = 3
@@ skipping 512 matching lines @@
       parser()->ReportMessage("accessor_get_set");
     }
     *ok = false;
   }
 }
 
 
 } }  // v8::internal
 
 #endif  // V8_PREPARSER_H